Az Eszterházy Károly Tanárképző Főiskola Tudományos Közleményei. 2004. Sectio Biologiae. (Acta Academiae Paedagogicae Agriensis : Nova series ; Tom. 25)
Zsoldos, F., Vashegyi, Á., Pécsváradi, A. and Bóna, L.: Aluminium toxicity in roots: correlation between root elongation and potassium fluxes in aluminium-sensitive and aluminium-tolerant cereal species
Aluminium Toxicity in Roots. 161 grown hydroponically for 7 days in different growth solutions under controlled conditions in growth chamber. At start of the growth period the low salt culture solutions contained 0.5 mM CaS0 4. Phosphorus (as phosphate) was added to the solutions at concentration of 0.1 and 1.0 mM. In growth experiments A1C1 3 was present at concentrations of 0 (control) and 0.05 mM. The initial pH values of growth solutions were adjusted with 0.1 M HC1 or 0.1 M NaOH as needed, and checked and renewed every day to maintain nutrient and Al concentration. Seedlings were illuminated for 16 h at about 65% relative humidity and 25/20°C day/night temperatures. The light intensity at plants level was 60 W m~ 2 (120 pmol mf 2 s" 1). Shoots and roots were harvested separately and plant parts were dried at 70°C to constant weight. Dry weights of all plant were determined upon harvesting. All experiments were performed in triplicate with whole plants, the data given below are averages with SD (n=8). A typical series of results from three independent experiments are presented in the figures. Potassium uptake experiments 8 6Rb was used to monitor the K + transport in plants (Erdei and Zsoldos 1977; Zsoldos et al. 2001). In the K"( 8 6Rb) influx experiments plants were precultured in 0.5 mM CaS0 4 solution in the presence or absence of phosphate. After the 7th day plants were transferred to different uptake solutions containing 1 mM K( 8 6Rb)Cl + 0.5 mM CaCl 2 + A1C1 3 and Na 2HP0 4 as indicated in figure legends. The pH of the absorption solution was initially adjusted to the appropriate value with 0.1 M HC1 or 0.1 M NaOH, and checked again at the end of the absorption period. The K +( 8 6Rb) influx experiments lasted for 6 hours. Roots and shoots were then separated and radioactivity of 8 6Rb in the plant material was measured by scintillation counter as described earlier (Zsoldos et al. 2001). Results In Figure 1 growth data are presented, showing that 50 pM Al concentration causes a significant decrease in root dry weight in the order of Al-tolerance [rye (17%)>triticale (20%)>common wheat (56%)>durum wheat (63%)]. Shoot growth was only moderately influenced in 7d experiments.
